Many enterprises have implemented a directory service to store and manage enterprise data, such as user data, user account data, group data, etc. The directory service can be hosted by a directory server and can store the enterprise data using a directory for all of the information in a single, network-accessible repository. The directory can be a directory that uses a lightweight directory access protocol (LDAP). The enterprise data in an LDAP-based directory may be replicated among a number of directory servers. Replication is the mechanism that automatically copies directory data from one directory server to another. Replication enables an enterprise to provide a highly available directory service and to distribute the enterprise data geographically. In practical terms, replication can help ensure that the directory is available even if some hardware, software, or network problem prevents directory client applications from accessing a particular directory server.
A directory server that holds a master copy of the information can automatically copy any updates to all replicas in other directory servers. However, replication that requires each directory server to communicate directly with every other directory server in a replication environment can restrict the resources of the directory server, which can negatively affect the performance of the directory server. In addition, a replication environment where each directory server communicates with every other directory server is not easily scalable and can limit the number of directory servers that can be deployed in the replication environment. When the resources of the directory servers that are currently deployed reach a maximum capacity, a system administrator cannot easily scale the replication environment.